Bourquin L D, Titgemeyer E C, Garleb K A, Fahey G C
Department of Animal Sciences, University of Illinois, Urbana 61801.
J Nutr. 1992 Jul;122(7):1508-20. doi: 10.1093/jn/122.7.1508.
Three dietary fiber sources (corn fiber, oat bran, wheat bran) were analyzed for chemical composition and potential fermentation by human colonic bacteria in vitro. Total dietary fiber (TDF) concentration of substrates was 64.3, 11.1 and 50.4 g/100 g dry matter for corn fiber, oat bran and wheat bran, respectively. Original material (ORIG), TDF fractions and simulated (SIM) cell wall fractions (produced by combining cellulose, hemicelluloses and pectic substances in proportions they represented in the cell wall) from each substrate were fermented in vitro for 6, 12, 18, 24 or 48 h using inoculum prepared from freshly voided feces from each of three human volunteers. Substrate dry matter remaining after 48 h of fermentation was 87.8, 39.8 and 73.5% for TDF fractions of corn fiber, oat bran and wheat bran, respectively. Disappearance of ORIG fractions was considerably greater than that of TDF due to fermentation of nonfibrous material. Disruption of cell wall structure during isolation of polysaccharide fractions allowed for dramatically increased fermentability of SIM relative to TDF. Averaged across all treatments, production of the short-chain fatty acids, acetate, propionate and butyrate, occurred in the molar ratio 63:21:16; however, profiles of short-chain fatty acids produced were influenced by both treatment and inoculum source. Extent of substrate fermentation varied among inoculum donors, implying that colonic microbial activities differ among individuals. Potential colonic fermentability of fiber sources was influenced by substrate, method of fiber preparation and inoculum source.
对三种膳食纤维来源（玉米纤维、燕麦麸、小麦麸）进行了化学成分分析以及人结肠细菌体外潜在发酵能力的研究。玉米纤维、燕麦麸和小麦麸底物的总膳食纤维（TDF）浓度分别为64.3、11.1和50.4克/100克干物质。使用从三名人类志愿者新鲜排出的粪便制备的接种物，将每种底物的原始材料（ORIG）、TDF组分和模拟（SIM）细胞壁组分（通过按它们在细胞壁中所占比例混合纤维素、半纤维素和果胶物质产生）在体外发酵6、12、18、24或48小时。玉米纤维、燕麦麸和小麦麸的TDF组分在发酵48小时后剩余的底物干物质分别为87.8%、39.8%和73.5%。由于非纤维物质的发酵，ORIG组分的消失明显大于TDF。多糖组分分离过程中细胞壁结构的破坏使得SIM相对于TDF的发酵能力显著提高。在所有处理中平均而言，短链脂肪酸乙酸、丙酸和丁酸的产生摩尔比为63:21:16；然而，所产生的短链脂肪酸谱受到处理和接种物来源的影响。底物发酵程度在接种物供体之间有所不同，这意味着个体之间的结肠微生物活性存在差异。纤维来源的潜在结肠发酵能力受底物、纤维制备方法和接种物来源的影响。
